PROJECT SUMMARY This T32 training program was established in 2014 to train the next generation of pre- and post- doctoral scholars in the prevention, treatment, and care of HIV and substance use among individuals in the criminal justice (CJ) system. The training program is a partnership between the Columbia University School of Social Work (SSW) and the Mailman School of Public Health (MSPH), with strong support from longstanding partnerships with a number of research centers, schools, and departments at Columbia University Medical Center. We propose to renew the program by continuing its unique position as the only NIDA-funded T32 program jointly run out of a school of social work and school of public health as well as the successful administration and activities; the renewal also proposes to focus on two key significant themes for the nation and the field: (1) the opioid epidemic; and (2) implementation science. The training program provides: (1) interdisciplinary research instruction and training for pre-doctoral students and post- doctoral fellows on the intersecting issues of substance use (particularly opioid use disorders and overdose), HIV, and implementation research with the CJ system and CJ-involved populations; and (2) hands-on, mentored experience conducting independent research in the study implementation of evidence-based HIV and/or substance use prevention, treatment, and care for criminal justice-involved populations. This program is designed to strengthen the pool of researchers by increasing the diversity of academic backgrounds?e.g., social work, public health, medicine, sociology, political science, anthropology?and those from underrepresented populations?e.g., underrepresented minorities (URM), people with disabilities, individuals from disadvantaged backgrounds. Participating faculty are leaders in HIV, substance/opioid use, implementation science, and criminal justice fields, with strong track records of support from NIH. They are also well-qualified to provide training, as evidenced by their strong records of mentorship of pre- and post-doctoral early career scholars. The program supports 4 pre-doctoral students and 4 post-doctoral trainees per year at capacity (a total of 6-8 pre-doctoral trainees and 8-10 post- doctoral trainees in the renewal period). Thus, the program will add a substantial number of highly qualified new scholars to the field focusing on HIV, substance use, opioid use disorders and overdose, and implementation science among criminal justice-involved populations. Dr. Nabila El-Bassel and Dr. Lisa Metsch will continue to serve successfully as PIs/Co-Directors for the proposed training program, which provides an opportunity for two noted and distinguished scientists to collaborate and lead this initiative. They each contribute over 25 years of experience in the fields of HIV, substance/opioid use disorder treatment and overdose prevention, implementation science, and criminal justice.